Encrypted messages sent via BlackBerrys are being used by mobs to encourage rioting across Britain - mayhem born of an incendiary mixture of conditions that converged during Europe's sleepy summer-vacation season.

Many of the masked or hooded youths have been photographed typing messages on their cellphones while flames engulf cars and buildings.

Conditions have been perfect for the unrest. Britain's economic outlook is bleak, youths are out of school and unemployed, police ranks have been depleted by summer vacations, and social-media sites, coupled with dramatic video of the rioting, have bolstered a mob mentality and spread disobedience.

Alcohol has also played a part. Some of Tuesday night's rioters bragged of booze-fueled rampages. Britain has a culture of binge drinking. The legal age to purchase alcohol in Britain is 18.

BlackBerry's messaging system is popular among youths because it's free, compatible with multimedia and private, compared with Facebook and Twitter. Its encrypted messages give troublemakers an added benefit: Police aren't able to immediately trace message traffic the way they can with regular cellphones.

Social media have been a potent force in fueling the riots that began Saturday in London's boroughs and later spread to other cities such as Birmingham, Liverpool, Leeds and Bristol. Messages have also been sent via regular texts and on Facebook.

One 18-year-old boy was detained Tuesday for allegedly encouraging violence on Facebook. Community members alerted police to the posts, according to police superintendent Athol Aitken. The teenager is expected in Dundee court on Wednesday.

But the social networks also have provided refuge for fearful residents and shop owners who say police efforts have been feeble and slow. Twitter is helping to pinpoint areas of violence, organize community cleanup groups and alert people of alternative routes they can use.

BlackBerry said it was cooperating with police, but shutting down the messaging system could penalize more than just the troublemakers. More than 45 million people use the BlackBerry messaging system worldwide.

"We feel for those impacted by recent days' riots in London," Patrick Spence, a Blackberry managing director of global sales and regional marketing, said in a statement. "We have engaged with the authorities to assist in any way we can."

David Lammy, a lawmaker from the Tottenham area where the rioting began, called for BlackBerry to suspend its messaging service. On Tuesday, hackers compromised BlackBerry's blog site in response to the company saying it would cooperate with police.